It happens occasionally in exhaust gas systems of internal combustion engines that individual components, such as exhaust pipes and housings of exhaust gas treatment devices, for example, such as catalysts, particle filters and sound absorbers, for example, must be fastened to one another. On principle, flanges can be used for this purpose.
In the event that a flow guiding function is to be assigned to the flange, it is possible, in principle, to attach a pipe section to the flange, which projects away from the flange at a longitudinal center axis, which is perpendicular to a flange plane. Such a pipe section can be welded to the flange, for example. The pipe section can serve as an inner wall for realizing an air gap insulation and/or as a feeding hopper or a discharge hopper, for example.
To weld the pipe section to the flange in a sufficiently reliable manner, a comparatively high wall thickness is required. So that the flange furthermore does not warp excessively in response to the welding of the pipe section, the flange must also have a comparatively large wall thickness. As a whole, the flange component part formed from flange and pipe section becomes comparatively expensive.